Costa Mesa police officers responded to a report of a man with a gun threatening someone on the 2900 block of Redwood Avenue at 6:25 p.m. Sunday. En route, gunshots were reportedly heard at the residence. When officers arrived, they heard one gunshot.
Inside the residence in a bedroom, officers found a 45-year-old woman with gunshot wounds to her chest. She was treated at the scene, then hospitalized, where she was pronounced dead.
Officers found the suspected shooter in the back yard, 48-year-old Thomas Wilhelm. He was detained and arrested for the shooting.
Police believe Wilhelm and the victim were arguing about a shared small business. Police determined the couple had been living together and the relationship was strained due to the shared business.
Police allege the argument escalated to the point of Wilhelm shooting the victim several times with a small-caliber handgun. Officers recovered a handgun at the scene.
Wilhelm is believed to have attempted to take his own life with a shotgun that misfired. He was uninjured when officers arrested him.
Wilhelm was booked for murder at the Costa Mesa Jail and was held on $1 million bond.
Anyone with information related to the investigation should contact the CMPD Detective Investigations Unit at (714) 754-5205.